The characteristic traits of German federalism are best explored in a historical analysis of the federal institutions. These exhibit a high degree of path-dependence that is due to the co-evolution of cultural orientations (unitarism) and of the institutional arrangements. The institutional arrangements were shaped in successive sequences of development (1849, 1867/71, 1919, 1945-49) which generated, due to complementary critical junctures, a system of increasing complexity that was more and more resistant to change. The longitudinal analysis shows that the institutional core of German 'unitary federalism' (as it has often been called) with its complex architecture withstands attempts at institutional engineering. However, the 'unitary' cultural orientations whose frame of reference was the nation state and which have contributed to the self-reproduction of this development path are now increasingly becoming obsolete. This might open windows of opportunity for greater decentralization.